It is generally difficult to manufacture a metal oxide/ceramic material having a uniform and homogeneous microstructure even when a mixture of fine particles of a plurality of kinds on inorganic powder materials is sintered or molten after being thoroughly kneaded. That is, in order to obtain a composite in the form of a homogeneous solid solution of a plurality of kinds of components, it is necessary to thoroughly homogeneously mix fine particles of those components. However, it is physically difficult to thoroughly homogeneously mix such components. Further, due to the differences of the melting points of those components, separation of one of the components having a higher melting point from another having a lower melting point inevitably occurs. Thus, it is very difficult to manufacture a composite having a thoroughly homogeneous microstructure which can satisfy the desired physical properties and functional requirements.
In an effort to solve such a problem, studies have been undertaken for manufacturing a metal oxide/ceramic material by baking a mixture of super-fine particles of a plurality of kinds of components having a fine particle size in the order of the angstrom unit. In spite of such an effort, satisfactory results have not yet been attained.
Thus, a composite including a ceramic component and a metal oxide component thoroughly homogeneously compounded together has not existed up to now. Even if such a composite were present, its physical properties could only be estimated from those of the individual components before being mixed.